Fluid activated vibratory device

ABSTRACT

A vibratory device comprising a hollow cylinder and a piston reciprocating in the cylinder is provided with a fluid channel system for deriving from the fluid pressure performances other than plain reciprocation of the piston.

United States Patent Felderhof et al.

[451 July 22, 1975 FLUID ACTIVATED VIBRATORY DEVICE Inventors: JanFrederik Felderhof, Voorburg,

Netherlands; James William Alfred Westwood, Upton upon Severn. EnglandFiled: Aug. 16, 1973 Appl. No.: 388,914

Foreign Application Priority Data Aug. 19, 1972 United Kingdom 38770/72Aug. 19, 1972 United Kingdom.... 38771/72 Aug. 22, 1972 United Kingdom38998/72 LS. Cl. 91/20; 91/234; 91/335; 91/437; 92/85 Int. Cl. F01]21/02 Field of Search 91/234, 341, 335, 232, 91/20, 437

[56] References Cited UNITED STATES PATENTS 1,940,388 12/1933 Callahan91/234 2,797,664 7/1957 Swanson 91/234 3,023,738 3/1962 Burgess, Jr.....91/234 3,601,009 8/1971 Burgess, 11* i 91/234 3,653,296 4/1972 Dexter91/335 Primary ExaminerPaul E. Maslousky [57] ABSTRACT A'vibratorydevice comprising a hollow cylinder and a piston reciprocating in thecylinder is provided with a fluid channel system for deriving from thefluid pressure performances other than plain reciprocation of thepiston.

18 Claims, 9 Drawing Figures PATENTEDJUL22 ms 1885581 SHEET 1 v FIG-1zuF u, 10

PATENTEDJUL 22 1915 SHEET FIG.5

FIG. 9

FLUID ACTIVATED VIBRATORY DEVICE The invention relates to a vibratorydevice, consisting of a combination comprising a hollow cylinderterminated by end plates, passages for a gaseous pressure fluid. inwhich passages are arranged ports for inlet to and exhaust from thecylinder, a piston which is reciprocably movable in the cylinder in andout an axial position in which the piston establishes communicationbetween an exhaust port and a working chamber in the cylinder in frontof the trailing side of the piston when moving to said axial position,the pressure fluid periodically moving the piston to said position whenacting on said trailing side and building up counter-pressure energy atthe opposite side of the piston. Such devices are used for example withvibratory conveyors.

Devices of this kind are known in which the piston is of the doubleaction type and in which a single inlet port is arranged and two exhaustports disposed equidistantly on either side of the inlet port, thepiston having two passages whereby the inlet port can communicate withthe working chamber in either end of the cylinder. It is also known toform either or both of the inter-engaging cylindrical surfaces of thepiston and cylinder from a material having a low co-efficient offriction and to run the device without an additional lubricant betweenthe surfaces. Nevertheless, there is still a need for devices of higherperformances in relation to their weight and costs.

An object of the invention is therefore to provide a vibratory device ofthe kind specified which can be operated more efficiently andeconomically in relation with the supplied pressure, which is operableover a wide range of frequencies and amplitudes and which is suitablefor transmittance of vibratory energies of varied intensity.

It is also an object to provide such a device which has small dimensionsin terms of its capacity to transmit energy and in terms of costs ofmanufacturing such device.

A vibratory device according to the invention is provide with fluidchannel means which enable to derive from the pressure fluid also otherfunctions than a plain reciprocation of the piston, such as cooling,control of readiness to start. control of preferred direction of energytransmittance, as will be elucidated herebelow.

The invention will now be described by way of example with reference tothe accompanying drawings in which:

FIG. I is a crosssectional side elevation view of a vibratory deviceconstructed in accordance with the invention:

FIG. 2 is an end elevation crosssectional view taken on the line II-IIof FIG. 1;

FIG. 3 is a cross-sectional side elevation view ofa further embodimentof the invention;

FIG. 4 is a cross-sectional side elevation view of an extended versionof the FIG. 3 construction;

FIG. 5 is a cross-sectional side elevation view of a yet furtherembodiment of the invention;

FIG. 6 is a cross-sectional side elevation view of the cylinder ofanother embodiment of the invention;

FIG. 7 is a crosssectional side elevation view of the cylinder of yetanother embodiment of the invention;

FIG. 8 is a cross-sectional side elevation view of a part of thecylinder of yet another embodiment of the invention; and

FIG. 9 is a cross-sectional side elevation view of a multipistonembodiment of the invention.

Referring to FIGS. 1 and 2 of the drawings. there is shown a cylinder 10closed at its ends by end plates 11 and 12 respectively, which aresecured by bolts 13. A radially disposed inlet port 14 for a fluid suchas pressurized air is positioned mid-way between the ends of thecylinder. Two radially disposed outlet ports 15 and 16 are situated inthe cylinder wall with their axes at right angles to the axis of inletport 14. These ports are axially disposed at equal distances on eitherside of the inlet port 14. In other embodiments of the invention, theoutlet ports 15 and 16 may be situated at any radial position in thecylinder wall so long as they are equally axially spaced on either sideof the inlet port 14.

Within the cylinder there are two axially spaced bearing sleeves l7 and18 defining between them an annular groove 19 which communicates withthe inlet port 14.

The sleeves in this example are made from polytetrafluoroethylene.Another example of a material from which the bearing sleeve may be madeis lead bronze which is impregnated with graphite. Such a bearing sleevecan be used as a bearing without any additional lubricant.

Axially aligned with the respective outlet ports 15 and 16 and extendingaround the respective outer surfaces of the sleeves l7 and 18 are twofurther annular grooves 20 and 21. These grooves are situated mid-waybetween the ends of the sleeves respectively and communicate each withan opening 22 in the sleeves respectively. The openings 22 extend intothe internal surface of the respective sleeves l7 and I8 and are p0-sitioned so as to be diametrically opposite to the respective outletports 15 and I6.

Mounted for axial sliding movement within the sleeves is a piston 24,which has two L-shaped passageways and 26. Each of these passageways hasan axially extending portion and a radially extending portion andcommunicate with the opposite working chambers 27 and 28 in the cylinderrespectively. When the piston moves axially in one direction from itscentral position as shown mid-way between the ends of the cylinder, oneof the passageways communicates with the groove 19. Similarly, when thepiston 24 moves in the other direction, the other passagewaycommunicates with the groove 19. The respective axial portions of thepassageways 25 and 26 are over half as long as the piston 24. When thepiston 24 is in its central position as shown, neither of thepassageways 25 and 26 can communicate with the groove 19. However, whenpressureized air is applied to the inlet port 14, some leakage flowbetween the piston and the internal surfaces of the sleeves can takeplace, with preference for the air reaching one of the chambers 27 and28 directly or after passing through one of the passageways 25 and 26,so as to build up a slight overpressure in one of the chambers. Aspecial leak groove 29 of very small cross-sectional area provided inthe surface of the piston 24, for the device to start to operate.

The pressurized air expands in the chambers 27 and 28 and flows to theexhaust ports 15 and I6 respectively through the circumferential grooves20 and 21 respectively cooling effectively the sleeves I7 and 18,respectively.

Numeral 30 denotes a mounting ear.

In use, pressurized air is applied to the inlet port 14. Air will thenreach one end of the cylinder through one of the passageways 25 and 26.This will cause the piston to move. When the piston has moved apredetermined axial distance under the action of this pressure, theother passageway will communicate with the groove 19 and the inlet port14 and thus admit pressurized air to the other end of the cylinder. Therate of vibration of the piston is principally dependent upon thepressure of the air entering and the mass, or inertia, of the piston.

Referring to FIG. 3 there is shown a vibratory device similar to thatshown in FIGS. 1 and 2 of the drawings but with the cylinder formed fromthree annular portions 31, 32, and 33, secured together by bolts 13'.There is shown in FIG. 4 a vibratory device which is an extension of theFIG. 3 construction, the cylinder being composed of five annularportions 34 to 38 respectively secured together by bolts 13. This longerversion of the vibratory device accommodates a larger piston and for agiven inlet pressure this provides slower vibration and higher power.The outlet ports in the wall of the cylinder are not shown in FIGS. 3and 4. The end plates 41 and 42 of the FIG. 3 construction haverespective central through holes 43 and 44. Connected to the end plates41 and 42 and communicating with the holes 43 and 44 are respectiveL-shaped pipe adaptors 45 and 46 which are interconnected at their outerends by a U-shaped tube 47, which is provided with a control valve 48,the parts 45, 46, 47 forming a by-pass between the working chambers. Inthe FIG. 4 embodiment a corresponding by-pass 49 is formed by holesdrilled in the end plates 39 and 40 and in the annular portions 34-38.The by-pass 49 is at either end provided with control valves 50 and 51respectively. With the interconnection of the working chambers thefrequency and amplitude of the vibrations produced by the device can beadjusted.

Referring to FIG. 5, there is shown a device similar to the device ofFIG. 1, however, the FIG. device has a cylinder composed of threeannular portions 61, 62, 63 and futher has exhaust ports 66 and 67respectively, which are provided with respective adjustable throttlevalves 68 and 69. Each of the valves 68, 69 has a central member 70which comprises a frusto-conical part 71, a hexagonal flange 72 formedintegrally with the conical part 71 on its larger end, and respectiveaxially aligned threaded cylindrical portions 73 and 74 extending fromthe smaller end of the conical part 71 and the flange 72 respectively.The cylindrical portions 74 of the valves 68 and 69 engage screw threadson the internal peripheries of the outlet ports 66 and 67 respectivelyand the flanges 72 abut against outer edges of the ports 66 and 67.Extending axially through the cylindrical portion 74, the flange 72 andthe frusto-conical part 71 of each of the valves 68, 69 is a bore 76.This bore communicates with a through cross drilling 77 which extendstransversely of the bore 76. Surrounding the frusto-conical part 71 is acap 78 having a stepped bore 79 the larger section of which is taperedso as to be corresponding in shape to the conical part 71. The smallersection of the stepped bore 79 is screw-threaded and engages the screwthread of the cylindrical portion 73 of the central member 70. Rotationof the cap 78 varies the distance between the complementary taperedsurfaces and thus provides a variable restriction to any fluid flowingout of the respective exhaust port and along the bore 76 and thedrilling 77. The exhausting air is thus directed back over the outersurface of the vibratory device for cooling purposes. A locking nut 80engages the outer end of the cylindrical portion 73, to lock the cap 78in position thereon.

By means of these throttle valves 68, 69, the restrictions in theexhaust ports 66 and 67 respectively can be adjusted and thus thefrequency and amplitude of the oscillation of the piston controlled. Anincreased restriction results in a rise of the frequency and a reductionof the amplitude.

The throttle valves 68, 69 can be adjusted differently. whereby theaverage pressure in one working chamber will differ from that in theother working chamber, resulting in a preferred direction of energytransmittance.

A similar effect will be brought about by inlet or exhaust ports ofdifferent diameter and, or, a difference between the respectivedistances of the exhaust ports to the inlet port of the cylinder seenaxially thereof. In the FIG. 6 embodiment the exhaust ports 81, 82 inthe inner sleeves 83 and 84 respectively are at unequal distances fromthe inlet port 85 and the annular groove 86, the exhaust ports 87, 88 inthe outer cylinder being correspondingly positioned. In the FIG. 7embodiment the exhaust ports 91, 92 in the inner sleeves 93 and 94respectively and the corresponding exhaust ports 97, 98 in the outercylinder wall have a different diameter. but equal distances from theinlet port and groove 96.

Referring now to FIG. 8, there is shown a part of an embodiment in whichthe cylinder. composed of an outer cylinder wall and sleeves 111, isclosed at its end by and end plate 112 secured by bolts 113. In acentral screw threaded bore in the plate 112 is fixed a spring device114, acting in the embodiment shown with compressed air, introduced andregulated in pres sure via the conduit 115, which spring device can alsobe of the metal spring type. The piston rod 116 cooperates each cycle ofvibration with the piston, which is not shown. By means of the actingair pressure in the device 114 the characteristics of the createdvibration can be regulated. A spring device 114 can also be fitted atthe opposite end of the cylinder 110, 111 and can be combined with othercontrol means as described hereabove.

In FIG. 9 there are shown three axially aligned interconnected vibratorswhich act as a single vibratory unit.

The cylinders are each composed of an outer cylinder wall consisting ofthree annular parts 121, 122, I23, and inner sleeves 124, 125, eachhaving an annular groove 126 for communication between an exhaust portin a sleeve and a diametrically opposed exhaust port in the surroundingannular outer wall part, which parts are not shown. In each of theinterconnected vibrators is mounted a piston 127 provided with two L-shaped passageways 128 and 129 for the periodical communication betweenthe working chambers at either end of the piston with the inlet port 130via the annular groove 131. The adjacent pistons are joined by a rod 132which has screw-threaded ends 133 and 134 respectively, which threadedlyengage tapped bores in the pistons respectively. Respective flats 133aand 134a are indicated adjacent either end of the rods 132 to enablegripping of the rod when screwed to a piston.

The rod 132 between the intermediate piston 127 and the piston 127 atthe right side in the figure is journalled at around its mid-portion bya dry bearing sleeve 135 secured in the separating plate 136. The rod132 joining the piston 127 at the left hand side of the figure with theintermediate piston is journalled in a pair of seals 137, eachcomprising a ring 138 of shallow rectangular cross-section surrounded byan O-ring 139, which seals 137 are mounted in the separating plate 140.The end plates 141 and 142 are secured by bolts 143 further passingthrough holes in the annular parts 121, 122, 123 and the separatingplates 136, 140. In the end plate 142 is mounted a dry bearing sleeve144 through which passes a piston rod 145 for joining of the combinedpistons 127 to another device, not described herewith.

Pressurized air introduced through the respective inlet ports 130 willcause the pistons 127 to move in unison, each controlling the flow ofthe air just as described in relation with the other embodiments.

An advantage of the multi-piston device, when the pistons are rigidlyunited, is that each of them can be short without danger of cantingwhich could cause high friction and quick wear. A special advantage isthat a multi-piston device, compared with a single piston device has agreater piston area on which the pressure fluid can act in relation topiston weight and lengths of the channels for the flow of the fluid, andthus the resistance to this flow, resulting in greater frequency of thevibration and higher energy transmitted.

We claim:

1. A vibratory device comprising a hollow cylinder with terminal endplates, an inner sleeve fitted in said cylinder and extending betweensaid end plates, said cylinder having an inlet for a gaseous pressurefluid, said sleeve having an inlet opening in registry with said inletin the cylinder for flow of the pressure fluid therethrough, and apiston slidably mounted in said sleeve for undergoing reciprocatingmovement therein, said inner sleeve having a pair of axially spacedexhaust ports, said inner sleeve and cylinder defining twocircumferential passages therebetween each in axial registry with arespective exhaust port, said cylinder having two outlet ports each incommunication with a respective circumferential passage and therethroughwith a respective exhaust port, each outlet port in the cylinder beingcircumferentially displaced with respect to the associated exhaust portin the inner sleeve, said piston being provided with two passageways,each for establishing communication between the inlet opening in thesleeve and a respective working chamber formed between one end of thepiston and one terminal end plate, said piston in the course ofreciprocating movement passing through respective axial positions inwhich the piston successively covers and uncovers each exhaust port inthe inner sleeve.

2. A vibratory device according to claim 1, in which the piston in anintermediate position closes the inlet opening for the inlet of pressurefluid, and means allowing leakage flow of pressure fluid to one end sideof the piston as compared to the other end side of the piston in itsintermediate position.

3. A vibratory device according to claim 2, in which said means allowingleakage flow is an axial groove in said piston for said leakage flow.

4. A vibratory device according to claim 1 further comprising means ateach of said outlet ports of said cylinder for individually andselectively varying fluid flow therethrough.

5. A vibratory device according to claim 4 wherein said means at eachoutlet port comprises an adjustable throttle valve.

6. A vibratory device according to claim 5 wherein each throttle valveincludes an adjustable cap defining a stepped bore having an outletfacing the external surface of the cylinder and inclined theretowards todirect exhausted fluid onto the outer surface of the cylinder.

7. A vibratory device according to claim 1, in which said exhaust portsfor the exhaust of the pressure fluid are arranged axially at eitherside of said inlet port for the inlet of the pressure fluid, such thatthe axial spacing between one exhaust port and the inlet port differsfrom the spacing between said inlet port and the other exhaust post.

8. A vibratory device according to claim 1 comprising a spring on atleast one of the end plates for accumulation of counterpressure energyperiodically derived from the pressure fluid and for cooperation withthe piston for transmittance of said energy thereto, said spring beingadjustable.

9. A vibratory device according to claim 8, in which said spring is anair pressure spring.

10. A vibratory device according to claim 1, comprising guide means forguiding exhausted fluid onto the outside surface of said cylindner forcooling the same.

11. A vibratory device according to claim 1, comprising a by-passconduit connecting both said working chambers.

12. A vibratory device according to claim 11, comprising a regulatingvalve in said by-pass conduit.

13. A vibratory device according to claim 1, comprising a plurality ofpiston-cylinder combinations assembled in axial relationship, thepistons of adjacent combinations being connected by a connecting rodwhich passes through an end-plate of each of the adjacent cylinders.

14. A vibratory device according to claim 13, in which the pistons ofadjacent combinations are rigidly connected.

15. A vibratory device according to claim 13, in which adjacentcylinders at their facing ends are terminated by one and the same endplate.

16. A vibratory device according to claim 1, wherein said cylindercomprises a plurality of cylindrical rings secured together in axialrelationship.

17. A vibratory device according to claim 1 wherein said cylinder has auniform cylindrical outer surface.

18. A vibratory device according to claim 1 wherein said exhaust portsin the inner sleeve and said outlet ports in the cylinder are inrespective diametric opposition to one another.

1. A vibratory device comprising a hollow cylinder with terminal endplates, an inner sleeve fitted in said cylinder and extending betweensaid end plates, said cylinder having an inlet for a gaseous pressurefluid, said sleeve having an inlet opening in registry with said inletin the cylinder for flow of the pressure fluid therethrough, and apiston slidably mounted in said sleeve for undergoing reciprocatingmovement therein, said inner sleeve having a pair of axially spacedexhaust ports, said inner sleeve and cylinder defining twocircumferential passages therebetween each in axial registry with arespective exhaust port, said cylinder having two outlet ports each incommunication with a respective circumferential passage and therethroughwith a respective exhaust port, each outlet port in the cylinder beingcircumferentially displaced with respect to the associated exhaust portin the inner sleeve, said piston being provided with two passageways,each for establishing communication between the inlet opening in thesleeve and a respective working chamber formed between one end of thepiston and one terminal end plate, said piston in the course ofreciprocating movement passing through respective axial positions inwhich the piston successively covers and uncovers each exhaust port inthe inner sleeve.
 2. A vibratory device according to claim 1, in whichthe piston in an intermediate position closes the inlet opening for theinlet of pressure fluid, and means allowing leakage flow of pressurefluid to one end side of the piston as compared to the other end side ofthe piston in its intermediate position.
 3. A vibratory device accordingto claim 2, in which said means allowing leakage flow is an axial groovein said piston for said leakage flow.
 4. A vibratory device according toclaim 1 further comprising means at each of said outlet ports of saidcylinder for individually and selectively varying fluid flowtherethrough.
 5. A vibratory device according to claim 4 wherein saidmeans at each outlet port comprises an adjustable throttle valve.
 6. Avibratory device according to claim 5 wherein each throttle valveincludes an adjustable cap defining a stepped bore having an outletfacing the external surface of the cylinder and inclined theretowards todirect exhausted fluid onto the outer surface of the cylinder.
 7. Avibratory device according to claim 1, in which said exhaust ports forthe exhaust of the pressure fluid are arranged axially at either side ofsaid inlet port for the inlet of the pressure fluid, such that the axialspacing between one exhaust port and the inlet port differs from thespacing between said inlet port and the other exhaust post.
 8. Avibratory device according to claim 1 comprising a spring on at leastone of the end plates for accumulation of counter-pressure energyperiodically derived from the pressure fluid and for cooperation withthe piston for transmittance of said energy thereto, said spring beingadjustable.
 9. A vibratory device according to claim 8, in which saidspring is an air pressure spring.
 10. A vibratory device according toclaim 1, comprising guide means for guiding exhausted fluid onto theoutside surface of said cylindner for cooling the same.
 11. A vibratorydevice according to claim 1, comprising a by-pass conduit connectingboth said working chambers.
 12. A vibratory device according to claim11, comprising a regulating valve in said by-pass conduit.
 13. Avibratory device according to claim 1, comprising a plurality ofpiston-cylinder combinations assembled in axial relationship, thepistons of adjacent combinations being connected by a connecting rodwhich passes through an end-plate of each of the adjacent cylinders. 14.A vibratory device according to claim 13, in which the pistons ofadjacent combinations are rigidly connected.
 15. A vibratory deviceaccording to claim 13, in which adjacent cylinders at their facing endsare terminated by oNe and the same end plate.
 16. A vibratory deviceaccording to claim 1, wherein said cylinder comprises a plurality ofcylindrical rings secured together in axial relationship.
 17. Avibratory device according to claim 1 wherein said cylinder has auniform cylindrical outer surface.
 18. A vibratory device according toclaim 1 wherein said exhaust ports in the inner sleeve and said outletports in the cylinder are in respective diametric opposition to oneanother.